【Purposes】 The stress on the metro wheel is complicated, which is not only influenced by the wheel-rail coupling force and the contact pressure induced by the axle-wheel interference fit, but also by the thermal load generated during braking. 【Methods】 In this paper, a metro wheel with single S-type spoke plate is taken as the research object. The finite element model of the wheel is established in ABAQUS software and the influence of the axle-wheel interference fit is analyzed on the mechanical stress distribution of the wheel under the straight-line load condition. The thermal-mechanical coupling model of the wheel is established at tread braking under the turnout load condition. The direct coupling method is used to study the variation of the temperature and stress fields of the wheel. Effects of mechanical stress and thermal-mechanical coupling stress on the structural strength of the wheel under different wear levels are studied. 【Findings】 Results show that the thermal load mainly affects the structure near the tread, while the part near the hub is greatly affected by the interference fit. The maximum difference of coupling stress between the new wheel and the worn-to-limit wheel is up to 69.3 MPa. The coupling stress of the wheel is relatively stable within the diameter range of 820-840 mm, with a float of only 9.1 MPa. 【Conclusion】 This study provides scientific reference for the structural design of metro wheels and can give a good guidance for the maintenance work.